Pressure switch contacts



NOV-V -1'2 1963 P. H. WILLIAMS E'rAl. 3,110,784

` PRESSURE SWITCH CONTACTS Filed July l, 1960 lh l1 2 Sheets-Sheet 1f-Io v /-f--Uw vz?" 1...'. 1- 1 ir.. I6

44 l 6 54 56 I 8 5B v se I 7l 5a 4 56 58 41|. l r: 'h1 l*I 1| l 1H, d

.11; INVENTORS 54 IH Paul H. Williams und lll FI G2 IW/Z// Attorney NOV12, 1963 P. H. wlLLlAMs ETAI. 3,110,784

PRESSURE SWITCH CONTACTS Filed July 1, 1960 2 sheets-sheet 2 FIGS .A se

INVENTORS Paul H. Williams und BY Joseph J. Koleba ,fw/,WMM

Aftorney 3,llt),74 PRESSURE SWHCH CNECTS Paul H. Williams, Elmhurst, andlaseph E. Kalcba,

Roselle, lll., assignors to Controls Company of America, Schiiier Park,lll., a corporation ot Delaware Filed Early-l., 196?, Se No. 40,267 l2Claims. Cl. 26d-83) This invention relates to pressure switches of thetype used to determine the water level in washing machines and the like.

Pressure switches of the generalV type shown here have a diaphragmsubjected to water pressure to actuate a switch `when a predeterminedpressure (corresponding to a desired water level) obtains. The usualoperation is to have the switch continue the filling of thecontaineruntil yit reaches the desired level, whereupon the control shuts offwater ilow and continues the washing machine cycle. Therefore, thefunction `of the pressure switch is to signal when the desired level isreached. The level is selected by manually actuating a cam which variesthe bias on the diaphragm opposing lthe water pressure. The cam ispreferably shaped -as in Beller Patent Ser. No. 2,934,618 and isprovided with lobes which act to reset the switch to its normal (notfull) position between different settings. lt is possible, however, tohang-up the Beller selector on a lobe with the result that the switch isheld closed-calling for water and unable to openaiiowing the water tocontinue to flow, causing a ilooding condition.

The primary object `of this invention is to prevent locking of thepressure switch in the till position under the aforementionedconditions.

Other objects and advantages lwill be pointed out in, or be apparentfrom, the specification and claims, as will obvious modicaticns of thesingle embodiment shown in the dpawings, in which:

FIG. l is a side elevation of a fluid pressure responsive switch;

FIG. 2 is taken on line 2--2 of FIG. l showing the v switch in theclosed position;

FlG. 3 is similar to RIG. 2 showing the switch in the neutral orinoperative position;

FIG. 4 shows the plunger extension used to lock the switch in neutral;and

lFlG. 5 is a fragmentary exploded perspective further illustrating thearrangement of the parts.

Referring more particularly to the drawings, the iluid pressureresponsive device includes pressure tube lil secured to cup i4 which ismounted Von the shoulder 16 of an insulated housing i8. Diaphragm Ztl isclamped between the housing and the cup and divides the housing into apressure chamber 22 and a switch chamber 24. The pressure tube isprovided with orice l2 so that the pressure chamber will be incommunication with the huid being measured. Diaphragm pa-d 2o has adownwardly extending stud 28 having a reduced lower end portion whichprojects through a cooperating hole in tongue 32 of switch blade 34. Oneend of the blade is secured to external Contact y36 by rivet S8 and isprovided with double contact 4d on its free end. Barrel spring d2 iscompressed between the tongue and the blade to normally bias the doublecontact into engagement with upper switch contact ed which is connectedin the water till circuit.

When water is -run into the machine, pressure will build up in chamber22 pushing the diaphragm down and compressing spring 46 between stud 28and cylinder The tongue will move down with the stud compressing thebarrel spring until it passes the plane ofthe blade, snapping the bladeupward with the double contact enarent Patented Nov. l2, lQS

. in the housing. Lobes 5d .are provided on the cam between the `valleys-to reset the switch when the cam is rotated by pushing the cylinder upand causing projection ed to push the tongue up until the bladesnaps-back into engagement with the till contact 44.

in the prior Beller device it was possible in some instances `for thecam 'follower 55 'on the cylinder to hang up on the lobes with theprojection 60 holding the tongue down so that it coul-d not respond tothe pressure on the diaphragm, .thus preventing interruption of the tillcircuit and allowing the machine to -overll and flood the area. Toprevent this situation bracket 62 is mounted in hole to normally rest onovertravel spring i66 positioned between the bracket and flange 7l ofcylinder 48 (see FRG. 2). ln this position the bracket has no elect onthe switch operation but when the resetcam 54 is rotated to bring a lobe5S under thewfollower 55 the cylinder moves up .and raises the bracketuntil tabs 68 abut the underside ot ange itl (with spring 66accommodating overtravel of the cylinder while holding the bracketfirmly against the iiange). At this time the positive reset pin i9`forces diaphragm pin Z8 upwardly so spring te can move the tongue 32overcenter to tend to trip tie switch back to contact 44. With thebracket positioned las shown in FlGS. 3 and 5, however, the legs 72 ofthe bracket prevent the rails 65 of the blade 34 from moving down, thusacting to hold the switch 4in an incompleted tripped position -as shownin FIG. 3. This incompleted tripped position is held as long as the lobeis under the -follower, thus preventing machine operation so long as thereset is hung-up. The contacts del and Si? are located a relativelysmall distance apart so that a small motion of blade 34 will open onecircuit and close the other. Since the mounts for these contacts andiiange "tl are mol-ded with lthe housing, the vertical distance betweenthem can be very accurately determined. With this relationship known,the sides of the bracket can be easily made equal to the distance ifromthe tlange to a horizontal line drawn between the contacts. Since theserelationships are all predetermined, the bracket lends itself readily tomass production type fabrication.

ln operation, cam 5d is manually rotated to the desired level. Normally,the cylinder will be aligned with the valley S52 which has beenselected, providing the proper pressure on .the spring 46. When thepressure in chamber 22 is sutcient to move the diaphragm down, the biasof the barrel spring on the switch blade will be reversed, snapping theswitch from contact i4 to contact 50 to open the water lill circuit.When the pressure on the diaphragm is reduced, spring i6 will push thetongue upward, again reversing the bias of the barrel spring on theblade and closing the water ll circuit for the next cycle. lf thepressure is maintained in the pressure chamber and it is desirable toobtain a higher water level, the cam is rotated and lobes 53 will raisecylinder d8, causing pin 49 to push the tongue up, snapping the bladedown. Bracket 62 will also move upward, preventing the blade :fromengaging contact ed. lf the cylinder hangs up in lthis position, thewater ll cincuit will be open and water will ynot flow. It can :be seenthat the switch blade will always be biased in the down direction whenthe cam is rotated for resetting, due to the action of the plunger, sothat the lill circuit will be closed whenever the resetting motion isproperly completed.

Although but a single embodiment of the present invention has beenillustrated and described, it will be aparias/st- .9 parent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit of the invention or from thescope of the appended claims.

We claim:

l. A manually adjustable condition responsive device operated inaccordance with a condition comprising, control means, a member movablefto opera-te said control means in response to a change insaidcondition, loading means Iexerting a force on land opposing movementof said member in one direction, cam means operatively connected to theloading means and having multiple elevations each providing a differentbias on the loading means, reset portions between adjacent elevationportions ofthe cam, reset means operated by the reset portions, andmeans operative while the reset portion is effestive on the reset meansto prevent resetting and allowing completion of reset when the resetportion is not effective.

2. A manually adjustable condition responsive device operating inaccordance with a condition comprising, control means, a member movableto operate said control means in response to a change in said condition,loading means exerting a force on and opposing movement of said memberin one direction, cam means manually operable to diierent positions toadjust the force exerted by said loading means on said member, the`torce exerted by said loading means on said member being different indifferent positions of said cam means, resetting means actuated by thecam means between the ditierent positions of the cam means, said loadingmeans including means for preventing resetting when the resetting meansis effective and allowing completion of reset when the resetting meansis not etiective.

3. A manually adjustable -condition responsive device operated inaccordance with a condition comprising, control means, a member movableto operate said control means in response to a change in said condition,loading means exerting a force on and opposing movement of' said memberin one direction, cam means manually operable to different positions toadjust the force exerted by said loading means on said member, the forceexerted by said loading means on said member being diiierent indifferent positions of said cam, said loading means including means ttorpreventing operation of the control means when the loading means isloca-ted between the different positions on the cam` means.

4. A manually adjustable condition responsive device operated inaccordance with a condition comprising, control means, a member movableto operate said control means in response to a change in said condition,loading means exerting a force upon and opposing movement of said memberin one direction, a single multiple position cam manually operable todifferent positions thereof to adjust the forces exerted by said loadingmeans on said member, the force exerted by said loading means on saidmember being diierent in different positions on said cam, a reset memberoperated by said single cam when and as it is manually moved between itsmultiple positions to operate said control means, said loading meansincluding means for preventing operation of the control means when theiloading means is located between the different positions on the cam.

5. A manually adjustable condition responsive'device operated inaccordance with a condition comprising, a housing having a top wall witha hole therethrough opening tothe top of the housing, control means insaid housing, an actuator in said housing movable to operate saidcontrol means in response to a change in said condition, a plungerslidably guided in said hole for endwise up-anddown motion, a iirstspring confined underV compression between said plunger and saidactuator, a sleeve slidably guided in said hole `for endwise up-and-downmotion,

d said sleeve operatively engaging said contrJol means', a second springconfined under compression between said plunger and said sleeve, and cammeans mounted on the outside of said top wall of said housing, said cammeans acting upon said plunger and being manually oper-able to differentpositions to adjust the force exerted by said plunger on said actuator,the force exerted by said plunger on said sleeve between differentpositions of said cam member being sufficient to move the sleeve intocontact with the control means to prevent operation of the controlmeans, the force exerted by said plunger on said actuator beingdifferent in different positions of said cam means. 6. A manuallyadjustable condition responsive device according to clainr 5 includingresetting means operated by said cam means as said cam means is manuallyoperated between its diterent positions to operate said conv' posingtorce, the cam including re-set lobes between each position and actingon thevfollower, the follower including a reset member acting on theswitch when a lobe is eieotive to positively move the switch in adirection returning it to its normal position, and means effective onlywhen the reset member is eiieotive to blocl; return of the switch tosaid normal position. Y

8. A pressure switch according to claim 7 in which the means comprises arigid member limiting the switch motion toward the normal position sothat when so limited the switch is biased to said normal position butheld between its positions.

9. A pressure switch according to claim 8 including a second springacting between the follower and the rigid member and effective to seatthe rigid member against a iixed stop :for eiieotive limiting of theswitch motion only when a lobe is eiective, said second spring beingcompressible to take up any overtravel of the follower with respect tothe rigid member during resetting.

10. A pressure switch comprising, Ia housing including a diaphragmmovable in` response to pressure variations, a snap acting switch of thetype having elements stressed by an overcenter spring with one elementcarrying a contact movable between normal and actuated positions, anoperative connection between the diaphragm and the switch, a spring forloading the diaphragm, manual-ly operable means for determining thedegree of compression of the spring and actuatable to select any one ofa plurality of compressive loads, reset means operative whenever thecompressive load on the spring is changed to positively act on theswitch to move it overcenter in a direction returning the contact to itsnormal position, and means operative only when 4the reset means iseffective to prevent movement of the Contact to the normal position andto hold it in a position between said contact positions whereby movementto the normal position can occur only when the reset means has becomeinoperative.

1l. A pressure switch according to claim l() in which f the manual meansincludes a plunger mounted in the housing, the loading spring beingcompressed between the switch and the plunger, said last named meanscomprising a rigid member operative to seat against a housing portionand a second spring acting between the plunger and the rigid member andeiective to yieldably hold the rigid member seated as the plunger movesto reset theswitch, said member acting against one of the switchelements during resetting to prevent completion of movement of theContact to its normal position.

12. A pressure switch according to claim 11 in which the manual meansincludes a multi-position cam having valleys determining the position ofthe plunger and the force of the loading spring, said valleys beingseparated by reset lobes, the reset means comprising a rigid projec-References Cited in the le of this patent UNITED STATES PATENTS TyzackNov. 19, 1957 Hager Feb. 3, 1959 Lung Dec. 29, 1959 Beller et al Apr.26, 1960

1. A MANUALLY ADJUSTABLE CONDITION RESPONSIVE DEVICE OPERATED INACCORDANCE WITH A CONDITION COMPRISING, CONTROL MEANS, A MEMBER MOVABLETO OPERATE SAID CONTROL MEANS IN RESPONSE TO A CHANGE IN SAID CONDITION,LOADING MEANS EXERTING A FORCE ON AND OPPOSING MOVEMENT OF SAID MEMBERIN ONE DIRECTION, CAM MEANS OPERATIVELY CONNECTED TO THE LOADING MEANSAND HAVING MULTIPLE ELEVATIONS EACH PROVIDING A DIFFERENT BIAS ON THELOADING MEANS, RESET PORTIONS BETWEEN ADJACENT ELEVATION PORTIONS OF THECAM, RESET MEANS OPERATED BY THE RESET PORTIONS, AND MEANS OPERATIVEWHILE THE RESET PORTION IS EFFECTIVE ON THE RESET MEANS TO PREVENTRESETTING AND ALLOW-